Thermoketeh-case for steam-boilers



G. E. HAYESu Thermometer.

No. 28,172 Patented May 8, 186e;

GEORGE E. HAYES, OF

BUFFALO. NEW' YORK.

THERMOMETER-CASE FOB, STEAM-.BOILERS Specification of Letters Patent No. 28,172, dated May 8, 18,60.

To all whom it may concern:

Be it known that I, GEORGE E. HAYES, of Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Thermometers for Steam Apparatus; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l, is a front view of a thermometer constructed according to my invention. Fig. 2 is a central vertical section of the same at right angles to Fig. l. Fig. 3 is a horizontal. section of the same.

I Similar letters of reference indicate corresponding parts in the several figures.

In thermometers for steam purposes the mercury tube is ordinarily packed in the piece which screws into the boiler or steam vessel and the-.upper part of the said tube and the scale protected by a cylindrical metal case Whose bottom is secured to the piece which screws into the boiler by small screws. It requires but a very slight strain on this case to loosen the joint at its bottom and snap off the tube, and this accident is of frequent occurrence where such thermometers are used, more especially in dentists indiarubber or guttapercha vulcanizing apparatus in which owing to its position the thermometer forms too convenient a handle to prevent its being used as one by careless persons.

The principal object of my invention is to prevent such accident, and to this end my invention consists in making the case and the part in which the tube is packed in one piece and screwingihe same on to the exterior of the piece which screws into oris attached to the boiler substantially as yherein described.

My invention also consists in certain means applied in combination with a valve to the iece which attaches the thermometer to the boiler so that in small steam apparatus like that used by dentists for vulcan izing india-rubber or gutta-percha the said valve may be used both as a safety valve and a blow-off valve.

A represents the case having a female screw thread cut in the lower part of its interior the circumference of the interior of said screw thread being fully as large or rather larger than the upper portion of the interior of the case, in which the scale B, is received. Above the female screw thread there is formed around the interior of the case A, a fixed collar a, a, in opposite sides of which there are notches I), (see Fio. 3) to receive the scale which is inserted rom the bottom through the said notches. d, is the packing consisting of a ring of vulcanized india rubber fitting snugly around the exterior of the tube C, and to the interior of the lower portion of the case below the collar a, a; and e, and c', are two flat metal rings fitted loosely to the interior of the case and to the exterior of the tube C, one above and the other below the packing ring. The tube is slipped through the three rings d, e, and c', from the bottom of the case.

D, is a socket which has a screw thread g, on the lower part of its exterior to screw into a hole in the boiler or steam vessel and a screw thread l1., on the upper part of its exterior to fit into the female screw thread in the lower part of the case A. The case, having the three rings and the tube inserted, is screwed down upon the socket D, till the top of the said socket pressing against the bottom of the lower ring e, presses the ring e, up against the collar a, a, of the case with force enough to compress the packing ring el, closely around the exterior of the tube and the interior of the case, and makes a steam tight joint, at the same time securing the scale between the upper plate e, and the top of the case. With the case and tube thus secured, no strain can be brought upon the tube by the case, short of what will bend the case and that may be made as strong as can possibly be required.

z', is a safety valve fitted to a seat in one side of the socket D, and having a spring y', applied to give the requisite pressure to the valve. The head of the valve stem projects from a hollow boss c, on one side of the socket D, which constitutes a guide for it and in which there is an opening Z, for the steam to blow off. To the projecting head of this stem a bow m, is attached by a pin n, passing through them both, and the ends of the said bow are formed like cams as shown its seat to permit the steam to blowsT off, tight joint around the tube substantially as thereby making the Valve constitute not only a safety valve but a blow-ofi' valve.

What I claim as my invention and desire to secure by Letters Patent is:

1. Making the case and the part of the thermometer in which the mercury tube is packed in one piece and screwing the said piece on to a socket D, or its equivalent which secures the thermometer to the boiler or steam apparatus, in such manner as to compress the packing and make a steam herein specied.

2. And I also claim the boW m, Wit-h cam l5 like ends applied to a valve z', in the socket D, or its equivalent in combination With a spring j, substantially as and for the purpose herein specified.

GEO. E. HAYES. 

